Really wish I could help you. I'm in process of waiting and see if I have new BSOD. Just installed new RAM today. I think I might reformat and fresh install again in coupe days thought, just to make sure, before I get too many movies and series on my HD.
BTW did you try to fresh install again ? At least you've already eleminated lot of possibilities, you're getting closer to the problem. Hopefully, you like me, will get the things fix soon.
I do not think running dx11 in windows 7 and having a directx10 card cause a big problem. However, that's a good question you just get to my attention. I did not noticed before that I was in this situation too.
Hopefully someone more skilled can answers your question properly.